ABSTRACT Support is requested for a Keystone Symposia conference entitled B Cells: Mechanisms in Immunity and Autoimmunity, organized by Drs. Lars Nitschke, Michael Reth, Roberta Pelanda and David M. Tarlinton. The conference will be held June 17-21, 2018 at Maritim Hotel & Conference Center in Dresden, Germany B cells play an important role in immunity and immunology research. New findings about the relevance and contribution of B cells to autoimmunity have rejuvenated interest in B cell immunology research. B cell functions unrelated to the production of antibodies have also been recently uncovered, indicating B cells operate in the context of both humoral and cellular adaptive immune responses. These B cell properties have stimulated a plethora of studies aimed at discovering the molecular mechanisms of B cell development and diversification, B cell activation, B cell memory responses and B cell tolerance induction. Affinity maturation of antibodies within the germinal center is now considered to be more complex than previously thought. The generation of broadly neutralizing antibodies against viruses in a few, but not all individuals, and the generation of autoantibodies during germinal center responses, have challenged existing dogmas. B cell metabolism and its intersection with the microbiome are stimulating and exciting areas only now beginning to be explored. For example, antibody- independent functions of B cells in secreting inflammatory or regulatory cytokines, suggest B cells are relevant in many inflammatory and allergic diseases. This conference aims to address the mechanisms of B cell activation, B cell differentiation and B cell responses, and the contribution of B cells to the development of autoimmune diseases. Finally, potential new treatment options for these diseases will be covered.